A sprite from my game’s tileset appeared in my game today after I drew some new tiles, sliced the tileset image, and put it into my tile palette. It uses the same sprite (a single tile) that appears when I drag my sliced tileset sprite into the scene (but is not a tileset, and didn’t make a materials folder like it does when I drag the tileset in). It is not in the hierarchy and can’t be deleted as far as I can tell (I’ve tried selecting everything in my scene from the hierarchy and deleting it and the tile is still there). Clicking the eye on the scene in the hierarchy to hide everything inside it doesn’t hide the sprite. The sprite is on the default sorting layer and shows up while playing the game as well as editing it. It isn’t on the tile grid and isn’t aligned to it either (it’s in the middle of two tiles).
I fixed this by making a new scene and copying everything from my old one into it. The sprite didn’t come into the new scene with everything else. Still have no idea how the sprite appeared.